Heat exchanger and condensing type laundry dryer having the same

ABSTRACT

A condensing type dryer uses a heat exchanger in which condensed water can be smoothly discharged through a water-discharging slot formed in a rear end portion of a rear cover of the heat exchanger. The water-discharging slot prevents an air flowing resistance which can be caused by condensed water pooling at the rear end portion of the rear cover. Also, leakage-preventing walls enhance the heat exchanging function by ensuring a uniform flow of cold external air through the heat changer. The leakage-preventing walls prevent external air from leaking around the lateral edges of the heat exchanger.

The present application claims priority to Korean Application No.10-2007-0018682, filed on Feb. 23, 2007 which is herein expresslyincorporated by reference in its entirety.

BACKGROUND

1. Field

The present invention relates to a heat exchanger for a condensing typeclothes or laundry dryer.

2. Background

In general, a drying apparatus such as a clothes dryer or a washingmachine having a drying function, dries clothes by blowing hot airgenerated by a heater into a drum. Such dryers can be divided intoexhausting (or vented) type dryers and condensing type dryers, dependingon the method used for processing the humid air generated when dryingclothes. In the exhausting or vented type dryer, humid air exhaustedfrom a drum is discharged to the outside of the dryer. In the condensingtype dryer, humid air discharged from the drum is condensed to removethe moisture therefrom, and the dried air is conducted back into thedrum again so as to be re-circulated.

A condensing type dryer typically includes a drum for containinglaundry, a filter for filtering out lint and foreign materials, and aheat exchange unit (or condenser) for removing moisture from hot dryingair which has flowed through the drum and absorbed moisture from thelaundry therein. The dryer also includes a fan for facilitating thedrying operation by generating air flow, a heater for heating the airflow to shorten the drying time, and pipes or vents for connecting thecomponents.

FIG. 1 is a side view schematically showing the internal components ofan example of a condensing type dryer. FIG. 2 is an interior plan viewof the condensing type dryer of FIG. 1. FIG. 3 is a perspective view ofa heat exchanger in the dryer of FIG. 1, and FIG. 4 is a lateral sideview of the heat exchanger of FIG. 3. The arrows I indicate a flow ofexternal cold air, and the arrows II indicate a flow of circulating hotair.

Referring to FIGS. 1 and 2, a drum 11 in which laundry is to beaccommodated is rotatably installed inside a main body 10 which isprovided with a door 12 installed at a front surface thereof. The drum11 is rotated by a belt 19 connected to a motor 17 installed at a lowerportion of the main body 10. A heat exchanger (or condenser) 13 isinstalled at a lower portion of the main body 10 and condenses moisturefrom hot and humid air that has been circulated through the drum 11 toremove the moisture from the air. Circulation ducts 14 a and 14 b whichare respectively connected with the front and rear end of the drum 11are connected with the front and the rear portions of the heat exchanger13, respectively. When air is discharged from the drum 11, it can beintroduced again into the drum 11 after passing through the heatexchanger 13.

A heater 15 for heating air which has passed through the heat exchanger13 and a circulation fan 16 for forcibly circulating the air through thecirculation ducts 14 a and 14 b are installed at the circulation duct 14a. The circulation fan 16 is connected with a different shaft of themotor 17 that also drives the drum 11.

In order to condense moisture from air circulated through thecirculation duct 14 a, a heat exchanging operation is conducted usingexternal cold air supplied to the heat exchanger 13. For this purpose,an external air supply duct 18 which communicated with the exterior ofthe main body 10 is connected with one side of the heat exchanger 13. Acooling fan 20 forcibly sucks in external air through the external airsupply duct 18 and discharges it into the main body 10. A cooling fandriving motor 21 drives the cooling fan 20. A filter 22 is used tofilter out foreign materials such as lint and waste thread or the likefrom the air exhausted to the circulation duct 14 a through the frontend side of the drum 11.

A water receiver (not shown) for collecting the water condensed duringthe condensation process is installed below the heat exchanger 13. Apump 23 is used to pump the condensed water collected in the waterreceiver to a condensed water storage tank 2.

Referring to FIG. 3, the external air passes through the lateral sidesurfaces of the heat exchanger 13 in the direction of the arrows I, andthe circulating air passes through the front and rear ends of the heatexchanger 13 in the direction of the arrows II. Through this process,heat exchange occurs in the heat exchanger 13 between the external airand the circulating air. The circulating air is cooled, which causesmoisture in the circulating air to condense and thereby be removed fromthe drum 11. The cooled and dried circulating air is then heated andblown into the drum 11 again so as to be re-circulated.

When moisture is condensed in the heat exchanger, it flows to theexposed lower end portion of the heat exchanger 13. The condensed watercollects at the lower end portion of the heat exchanger 13 (the partshown encircled by the dashed line in FIG. 3), which causes an airflowresistance, and the performance of the heat exchanger 13 isdeteriorated. Also, due to the obstruction caused by the pooledcondensed water, the flow of the external cold air is forced towards thelateral edge regions of the heat exchanger 13, as shown within thedashed lines in FIG. 4. As a result, it is difficult to ensure a uniformdistribution of the external air flow. As a result, a drying performanceof the dryer may become deteriorated.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to thefollowing drawings, in which like reference numerals refer to likeelements, and wherein:

FIG. 1 is a view schematically showing the interior of a condensing typedryer;

FIG. 2 is a plan view of the interior of the condensing type dryer inFIG. 1;

FIG. 3 is a perspective view of a related art heat exchanger which canbe used in a condensing type dryer;

FIG. 4 is a side view showing a lateral surface of the heat exchanger inFIG. 3;

FIG. 5 is a perspective view of a first embodiment of a heat exchangerhaving improved water flow characteristics which can be used in acondensing type dryer;

FIG. 6 is a magnified partial view showing water-discharging slotsformed in a lower end portion of a rear cover of the heat exchanger inFIG. 5;

FIG. 7 is a side view showing a lateral side of the heat exchanger inFIG. 5 provided with leakage-preventing walls; and

FIG. 8 is a table comparing the performance of the heat exchanger inFIG. 5 with that of a conventional heat exchanger.

DETAILED DESCRIPTION

Referring to FIG. 5, a first embodiment of a heat exchanger 100 includesa heat exchange unit 110 in which a plurality of tubes 111 and finstructures 112 are alternately stacked. A front cover 130 covers a frontend of the heat exchange unit 110, and a rear cover 140 covers a rearend of the heat exchange unit 110. Leakage-preventing walls 150 areinstalled at lateral edges of the heat exchange unit 110.

Both ends of the tubes 111 may be opened and the tubes 111 may have aduct structure with a rectangular cross-sectional shape. Ducts or pipes(not shown), through which circulating air in the dryer flows,communicate with both ends of the tubes 111, respectively.

The fin structures 112 may be formed with air passages by the repeatedbending of a metal plate in a zigzag pattern. For example, the finstructures 112 may be bent in the zigzag pattern to form a rectangularparallelepiped structure having a fixed thickness, width and length atits exterior. If the metal plate is bent in a zigzag pattern, it may beformed into a repeated peak-and-valley structure. The upper and lowersides of the fin structure may be placed in contact with the surfaces ofadjacent tubes 111, respectively, and the fin structures can be joinedto the tubes. The fin structures provide passages for the external airto be introduced into the heat exchanger and to be discharged againafter undergoing a heat exchanging operation with air in the tubes 111.

The thickness of the fin structures 112 is based upon the sizes of thetubes 111 stacked thereon, and possibly based on the number of tube andfin structures that are stacked together. Preferably, the thickness ofthe fin structures is in the range of 8-10 mm. It is preferable that thetubes are thinner than the fin structures in order to increase the heattransfer rate. The tubes 111 and the fin structures 112 are made of ametal material with excellent heat transfer characteristics, andpreferably are made of aluminum or an aluminum alloy.

The front cover 130 and rear cover 140 may be coupled with the front andrear surfaces of the heat exchange unit 110, respectively. The front andrear covers 130, 140 may perform a coupling means function to allow theinlet and outlet of heat exchange unit 110 to be easily coupled with thecommunicating ducts or pipes in the dryer or with other components.

The front and rear covers 130, 140 may be made of a plastic materialsuch as ABS-GF. They would typically be formed by a method such asinjection molding. A sealing member or gasket may be additionallyinstalled at the portions where the front and rear covers 130, 140 arecoupled at both ends of the heat exchange unit 110 in order to preventthe leakage of air.

Referring to FIGS. 5 and 6, one or more water-discharging slots 141 maybe formed in the lower end portion of the rear cover 140 (dashed-lineoval portion in FIG. 5). A plurality of the water-discharging slots 141may be formed side-by-side, with the slots extending in the lengthwisedirection of the lower end portion or bottom lip of the rear cover 140.Condensed water can be smoothly drained and discharged through thesewater-discharging slots 141. This prevents the condensed water fromdeteriorating the performance of the dryer due to the generation of anair flowing resistance caused by the pooling of collected condensedwater at the rear end portion of the rear cover 140.

Referring to FIG. 7, leakage-preventing walls 150 may include a firstleakage-preventing wall 151 formed at the front cover 130 and coveringthe front lateral edges of the heat exchange unit 110 (dashed-line ovalportion in FIG. 7); and a second leakage-preventing wall 152 formed atthe rear cover 140 and covering the rear lateral edges of the heatexchange unit 110. The first leakage-preventing wall 151 and the secondleakage-preventing wall 152 can be integrally formed with the front andrear covers by extending the lateral ends of the front and rear covers130, 140 in the lateral direction of the heat exchange unit 110,respectively. Alternatively, the first leakage-preventing wall 151 andthe second leakage-preventing wall 152 can be separate additionalmembers that are welded or bonded to the lateral ends of the front andrear covers 130, 140 in the lateral direction of the heat exchange unit110, respectively. The leakage-preventing walls 150 enhance the heatexchanging function as the external air can be forced to flow uniformlythrough the fin units. The leakage-preventing walls prevent the coldexternal air from flowing around the ends of the fin structures at thefront and rear sides of the heat exchanger 100.

FIG. 8 is a table comparing the performance of a heat exchanger as shownin FIGS. 5-7 with that of a conventional heat exchanger. Referring toFIG. 8, a condensation type dryer having a heat exchanger as describedabove had a drying time that was approximately 4 minutes faster, areduced power consumption of 0.012 kWh less per 1 kg, and a condensingrate approximately 2% higher than the conventional dryer. Thus, theabove-described heat exchanger is excellent in its condensing ratecompared to a conventional heat exchanger. When the heat exchanger isemployed in a condensing type dryer, the power consumption and thedrying function of the dryer can be enhanced.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although a number of illustrative embodiments have been described, itshould be understood that numerous other modifications and embodimentscan be devised by those skilled in the art that will fall within thespirit and scope of the principles of this disclosure. Moreparticularly, variations and modifications are possible in the componentparts and/or arrangements which would fall within the scope of thedisclosure, the drawings and the appended claims. In addition tovariations and modifications in the component parts and/or arrangements,alternative uses will also be apparent to those skilled in the art.

1. A heat exchanger, comprising: a heat exchange unit in which aplurality of tubes and fin structures are alternately stacked, whereinair to be cooled and condensed enters the tubes at a front of the heatexchanger and exits the tubes through a rear of the heat exchanger, andwherein air used to cool the air in the tubes passes through the finstructures and enters and exits lateral sides of the heat exchanger; andat least one water-discharging slot formed at a lower portion of a rearof the heat exchange unit.
 2. The heat exchanger of claim 1, furthercomprising a rear cover covering the rear of the heat exchange unit,wherein the at least one water-discharging slot is formed on a lowerportion of the rear cover.
 3. The heat exchanger of claim 2, wherein theat least one water-discharging slot extends in a direction that issubstantially parallel to a direction of air flow exiting the tubes. 4.The heat exchanger of claim 2, wherein a plurality of water-dischargingslots are formed on the lower portion of the rear cover.
 5. The heatexchanger of claim 4, wherein each of the plurality of water-dischargingslots extend in a direction that is substantially parallel to adirection of air flow exiting the tubes.
 6. The heat exchanger of claim1, further comprising first and second leakage-preventing walls that areinstalled at the lateral sides of the heat exchange unit adjacent thefront and rear ends of the heat exchanger.
 7. The heat exchanger ofclaim 6, further comprising: a front cover mounted on the front end ofthe heat exchanger, wherein the first leakage preventing wall is coupledto the front cover; and a rear cover mounted on the rear end of the heatexchanger, wherein the second leakage-preventing wall is coupled to therear cover.
 8. The heat exchanger of claim 7, wherein the firstleakage-preventing wall is an extension of the front cover, and whereinthe second leakage-preventing wall is an extension of the rear cover. 9.The heat exchanger of claim 7, wherein the at least onewater-discharging slot is formed on a lower portion of the rear cover.10. The heat exchanger of claim 9, wherein the at least onewater-discharging slot extends in a direction that is substantiallyparallel to a direction of air flow exiting the tubes.
 11. The heatexchanger of claim 7, wherein the at least one water-discharging slotcomprises a plurality of water-discharging slots formed on a lowerportion of the rear cover and extending in a direction that issubstantially parallel to a direction of air flow exiting the tubes. 12.A condensing type laundry dryer comprising the heat exchanger ofclaim
 1. 13. A heat exchanger, comprising: a heat exchange unit in whicha plurality of tubes and fin structures are alternately stacked, whereinair to be cooled and condensed enters the tubes at a front end of theheat exchanger and exits the tubes through a rear end of heat exchanger,and wherein air used to cool the air in the tubes passes through the finstructures and enters and exits lateral sides of the heat exchanger; andfront and rear leakage-preventing walls that are installed at front andrear portions of the lateral sides of the heat exchange unit,respectively.
 14. The heat exchanger of claim 13, further comprising: afront cover mounted on the front end of the heat exchanger, wherein thefront leakage preventing wall is coupled to the front cover; and a rearcover mounted on the rear end of the heat exchanger, wherein the rearleakage-preventing wall is coupled to the rear cover.
 15. The heatexchanger of claim 14, wherein the front leakage-preventing wall is anextension of the front cover, and wherein the rear leakage-preventingwall is an extension of the rear cover.
 16. The heat exchanger of claim13, wherein the front and rear leakage-preventing walls prevent air fromflowing around sides of the fin structures.
 17. The heat exchanger ofclaim 13, wherein the front and rear leakage-preventing walls act todistribute the flow of air used to cool the air in the tubes more evenlythrough the fin structures.
 18. A condenser type dryer comprising theheat exchanger of claim
 13. 19. A heat exchanger, comprising: a heatexchange unit in which a plurality of tubes and fin structures arealternately stacked, wherein air to be cooled and condensed enters thetubes at a front end of the heat exchanger and exits the tubes through arear end of heat exchanger; and a rear cover mounted on a rear end ofthe heat exchanger, wherein at least one water-discharging slot isformed in the rear cover.
 20. The heat exchanger of claim 19, whereinthe at least one water-discharging slot comprises a plurality of waterdischarging slots that extend in a direction that is substantiallyparallel to direction of air flow exiting the tubes.